Mercury contamination in sandy soils surrounding an industrial emission source (Estarreja, Portugal)

Abstract

This study reports the degree and the extent of mercury contamination in sandy soils surrounding a chloralkali plant at Estarreja, Portugal. Total mercury concentration in the soils studied is at a maximum in the upper 5 cm, ranging from 117 to 49,233 μg kg−1. The profile distribution pattern for total mercury together with the results of a sequential extraction suggest that the element is strongly retained by the soil components. An upper limit of acceptable levels of mercury for this area is proposed based both on statistics and regulatory guidelines from other countries. Taking that limit, geostatistical methods were used to delimit a zone of heavy contamination. Atmospheric fall-out seems to be the main source of contamination of the soils studied.